Aceclofenac is a phenylacetic acid derivative that inhibits synthesis of the inflammatory cytokines interleukin-1b and tumour necrosis factor, and inhibits prostaglandin E2 production. It increases glycosaminoglycans (GAG) synthesis, the principal macromolecule of the extracellular matrix, which aids in repair and regeneration of articular cartilage. Thus, aceclofenac has +ve effects on cartilage anabolism combined with modulating effect of matrix catabolism. Paracetamol has analgesic and antipyretic action with weak anti-inflammatory activity. It produces analgesia by increasing pain threshold and antipyresis by acting on the hypothalamic heat-regulating centre.

ExcretionAceclofenac: About two-thirds of the administered dose is removed in the urine, mainly as conjugated hydroxymetabolites. Paracetamol: Most metabolites are removed in the urine within 24 hours.

Paracetamol: Reduced absorption of cholestyramine within 1 hour of administration. Accelerated absorption with metoclopramide. Aceclofenac: M0ay increase the plasma concentrations of lithium and digoxin. Increased nephrotoxicity with diuretics. Serum-potassium should be monitored when used with potassium-sparing diuretics. May enhance activity of anticoagulants. May increase plasma methotrexate levels leading to toxicity if administered within 2-4 hours of methotrexate admin. Risk of convulsions with quinolones.

Potentially Fatal: Paracetamol: Increased risk of liver damage in chronic alcoholics. Increased risk of toxicity with high doses or long term admin of barbiturates, carbamazepine, hydantoins, isoniazid, rifampin and sulfinpyrazone.